| Co-Investigator(Kenkyū-buntansha) |
浴野 稔一 広島大学総合科学部, 助手 (40185103)
鈴木 孝至 広島大学, 理学部, 助手 (00192617)
佐藤 憲昭 東北大学, 理学部, 助手 (30170773)
KOMATSUBARA T Faculty of Science, Tohoku Univ., 理学部, 教授 (80004331)
桜井 醇児 富山大学, 理学部, 教授 (30033814)
藤田 敏三 広島大学, 理学部, 教授 (20004369)
TAKABATAKE T Fac. of Integr. Arts & Sci., Hiroshima Univ., 総合科学部, 助教授 (40171540)
V Sechovsky Department of Metal Physics, Charles Univ., チャールズ大学金属物理学科, 教授
A DeVisser Van der Waals Laboratorium, Univ. of Amsterdam, アムステルダム大学ファン・デル・ワールス研究所, 研究員
J.J.M Franse Natuurkundig Laboratorium, Univ. of Amsterdam, アムステルダム大学・自然科学研究所, 教授
J.A Mydosh kamerlingh Onnes Laboratorium, Univ. of Leiden, ライデン大学カメリン・オンネス研究所, 教授
A.A Menovsky Natuurkundig Laboratorium, Univ. of Amsterdam, アムステルダム大学・自然科学研究所, 教授
SATOH N Faculty of Science, Tohoku Univ.
SAKURAI J Faculty of Science, Toyama Univ.
FUJITA T Faculty of Science, Hiroshima Univ.
SUZUKI T Faculty of Science, Hiroshima Univ. Univ.
EKINO T Fac. Integr. Arts & Sci., Hiroshima Univ.
NIEUWENBUYS ライデン大学, カメリンオンネス研究所(オランダ), 助教授
DEBOER F.R. アムステルダム大学(オランダ), 教授
SECHOVSKY V. チャールズ大学, 物理学科(チェコスロバキア), 教授
VISSER A De. アムステルダム大学, ファンデルワールス研究所(オランダ), 研究員
FRONSE J.J.M アムテルダム大学, 自然科学研究所(オランダ), 教授
MYDOSH J.A. ライデン大学, カメリン・オンネス研究所(オランダ), 教授
MENOVSKY A.A アムステルダム大学, 自然科学研究所(オランダ), 教授
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| Budget Amount *help |
¥6,000,000 (Direct Cost: ¥6,000,000)
Fiscal Year 1992: ¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1991: ¥3,000,000 (Direct Cost: ¥3,000,000)
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| Research Abstract |
In Monbusho International Scientific Research Program, we planned to make a searching study of new heavy-fermion systems in between Japan (Hiroshima Univ. and Tohoku Univ.) and Netherlands (Univ. of Amsterdam and Univ. of Leiden). In this course, we have found that some cerium and uranium intermetallic compounds display several interesting physical properties as Kondo-lattice ground states, depending on the degree of hybridizations of f-electrons with ligand s, p or d-electron states. The searching study has been independently performed in every university, keeping in close contact with each other. The results obtained are summarized as follows :
(1) In Hiroshima Univ., ternary compounds UCu_2Sn (hexagonal ZrPt_2Al-type structure) and UAu_2Al (orthorhombic YPd_2Si-type one) has been found to undergo antiferromagnetism below 17 and 25K and to reach electronicspecific heat coefficient gamma-60 and 102 mJ / mole・K^2, respectively, indicating intermediate heavy-electron states. Furthermore,
… More
we found that UCu_<3+x>Ga_<2-x> exhibit a maximum of T_N=17K at x=0.3 and a nonmagnetic heavy-fermion state evolves with further increase in x (gamma reaches 460 mJ/mole・K^2 at x=0.6). (2) Tohoku Univ. group have found a heavy-electronic character in U_2PtSi_3 (hexagonal AlB_2-type) with gamma-200 mJ/K^2・mole and an itenerant feromagnetic phase. (3) In Univ. of Leiden, psudo-ternaries U_3Ni_3Sn_<4-x>Sb_X have been found to indicate that the intermediate region with relatively low carriers is in a much heavier fermion state than the end member with x=0 (usual carrior).
Another aim in this project is to make single crystals of typical heavv-fermions and to perform systematic studies using them. As a typical material, we have focused on CeNiSn with a small-semiconducting energy gap in the Kondo-lattice ground state. Prof. Takabatake has grown its single crystal under the direction of Prof. Menovsky and measured the thermal expansion with Dr. de Visser in Amsterdam Univ. The result indicated that both alpha_a and alpha_b sharply decrease below 7K accompanied by the opening of an anisotropic energy gap. The neutron scattering experiments on CeNiSn are now in progress. Dr. Satoh has grown a single crystal of typical superconducting material UPd_2Al_3 and systematically studying the physical properties now.
In last September. we held the Workshop on transport and thermal properties of felectron systems in Hiroshima and could intenively discuss their mutual interesting problems within our collaboration groups. Finally, we agreed with a proposal keeping in close contact within our groups concerning heavy-fermion problems even after finishing this project. Less
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